Vehicle

ABSTRACT

Provided is a vehicle in which an electric motor is disposed such that a rotational axis of a rotor of the electric motor is located to one side, from the center of the front-back direction, relative to: a second power transmission member that is disposed on a power transmission path between a first rotating element and one wheel LWf; a third power transmission member that is arranged on a power transmission path between a third rotating element and the other wheel; or a differential mechanism.

TECHNICAL FIELD

The present invention relates to a vehicle.

BACKGROUND ART

Conventionally, an electric vehicle which is a vehicle in which thewheels are driven by a motor (electric motor) has been known (forexample, refer to Patent Document 1). The motor is arranged in apositional relationship whereby the extending direction of the outputshaft of the motor driving the right and left wheels of the vehiclematches the vehicle width direction which is the horizontal direction.

Patent Document 1: Japanese Unexamined Patent

Application, Publication No. H11-180172

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

In the case of the motor being arranged in a positional relationship inwhich the extending direction of the output shaft of the motor is ahorizontal direction and matches the vehicle width direction, theposition at which the output shaft of the motor is arranged is higher asthe diameter of the motor increases, and the motor becomes larger in thevertical direction. For this reason, it has been difficult to achievelowering of the center of gravity of a vehicle having a motor. Inaddition, it has been difficult to secure large capacity on the upperside of the front compartment. In addition, even if the diameter of themotor becomes larger, an increase in the crash stroke is demanded;however, in the case of the extending direction of the output shaft ofthe motor being the horizontal direction, and the motor being arrangedin a positional relationship matching the vehicle width direction, ithas been difficult to increase the crash stroke, and it has beendifficult to improve the protection of the passenger space.

The present invention has been made taking account of the above, and anobject thereof is to provide a vehicle which is capable of achievinglowering of the center of gravity of a vehicle having an electric motor,capable of ensuring large capacity at the upper side of the frontcompartment, and capable of achieving an increase in crash stroke andprotection of the passenger space.

Means for Solving the Problems

In order to achieve the above-mentioned objects, the present inventionprovides a vehicle (for example, the vehicle 3, 3A, 3B, 3C, 3D, 3E, 3Fdescribed later) including: an electric motor (for example, the electricmotor 300 described later) which drives a left wheel (for example, theleft-front wheel LWf described later) and a right wheel (for example,the right-front wheel RWf described later) of the vehicle, and has arotor (for example, the rotor 301 described later) and a stator (forexample, the stator 302 described later); and a differential mechanism(for example, the differential mechanism 400 described later) which hasthree rotating elements, and configured so that rotation speeds of thethree rotating elements satisfy a collinear relationship on a singleline in a collinear figure; in which the differential mechanism isdisposed on a power transmission path between the electric motor and theleft wheel and the right wheel; when defining the three rotatingelements as a first rotating element (for example, the left-side gear402 described later), a second rotating element (for example, thedifferential case 403 described later) and a third rotating element (forexample, the right-side gear 404 described later) in arrangement orderof the collinear figure, the first rotating element is mechanicallyconnected to one wheel (for example, the left-front wheel LWf describedlater), which is either one among the left wheel and the right wheel,the second rotating element is mechanically connected to the electricmotor, the third rotating element is mechanically connected to the otherwheel (for example, the right-front wheel RWf described later) which isthe other one among the left wheel and the right wheel; in which theleft wheel and the right wheel are disposed biasing to one side (forexample, the forward side of the vehicle 3 described later) relative toa center in a front/rear direction of the vehicle; in which the electricmotor is disposed so that the rotation axis of the rotor extends along avertical direction of the vehicle, and is disposed so that the rotor islocated lower than a first power transmission member (for example, thebevel gear 304, intermediate shaft 321, differential ring 401 describedlater) disposed on a power transmission path between the electric motorand the differential mechanism, and further is arranged so that therotation axis of the rotor of the electric motor is disposed so as to belocated more to the one side relative to the front/rear direction centerin relation to: a second power transmission member (for example, theleft-front drive shaft 501 described later) disposed on the powertransmission path between the first rotating element and the one wheel,a third power transmission member (for example, the right-front driveshaft 502 described later) disposed on the power transmission pathbetween the third rotating element and the other wheel, or thedifferential mechanism.

The crush stroke during collision of one side of the vehicle therebyincreases. For this reason, it becomes possible to further protect thepassenger space. In addition, since the rotor is arranged so as to belocated lower than the first power transmission member arranged on thepower transmission path between the electric motor and the differentialmechanism, the electric motor is arranged at a lower position in thevertical direction. For this reason, it becomes possible to make thevehicle lower center of gravity. In addition, it becomes possible tosecure the volume (spatial capacity) of the front compartmentcorresponding to the engine room of the vehicle in which the left wheeland right wheel are driven by an engine rather than an electric motor.In addition, since the rotation axis of the rotor is arranged so as toextend in the vertical direction of the vehicle, the electric motorbecomes a configuration in which the radial direction of the rotor ofthe electric motor matches the horizontal direction. For this reason, itbecomes possible to use a larger diameter motor as the electric motor.In addition, it is possible to secure the capacity (spatial volume) ofthe front compartment without harming the design or drivability of thevehicle.

In this case, it is preferable for the first power transmission memberto include: a first rotating body (for example, the bevel gear 304described later) disposed on a side of the electric motor on the powertransmission path; a second rotating body (for example, the differentialring 401 described later) disposed on a side of the differentialmechanism on the power transmission path; and a third rotating body (forexample, the intermediate shaft 321 described later) interposed betweenthe first rotating body and the second rotating body, in which the thirdrotating body is disposed so as to extend in the front/rear direction ofthe vehicle, and at least part of the electric motor is disposed so asto be located to the one side relative to the center in the front/reardirection, in relation to the second power transmission member, thethird power transmission member or the differential mechanism.

The third rotating body is thereby arranged so as to extend in thefront/rear direction of the vehicle body. For this reason, it becomes apositional relationship in which the electric motor is offset relativeto the differential mechanism in a side view. For this reason, theelectric motor is arranged closer to the front end of the vehicle. As aresult thereof, it is possible to further increase the crash strokeduring collision, and thus it becomes possible to further protect thepassenger space.

In addition, it is preferable for the second power transmission memberor the third power transmission member to be located more to the otherside relative to the center in the front/rear direction than an end (forexample, the rear end of the electric motor 300 described later) onanother side than the one side in relation to the center of thefront/rear direction of the electric motor. The electric motor isthereby arranged closer to the front end of the vehicle. As a resultthereof, it is possible to further increase the crash stroke duringcollision at the front of the vehicle, and thus it becomes possible tofurther protect the passenger space.

In addition, it is preferable for the electric motor to be disposed sothat the rotor is located more downwards than the second powertransmission member, the third power transmission member or thedifferential mechanism. The electric motor is thereby arranged at alower position in the vertical direction. For this reason, it becomespossible to make the vehicle a lower center of gravity. In addition, itbecomes possible to secure the volume (spatial capacity) on the upperside of the front compartment corresponding to the engine room of thevehicle in which the left wheel and right wheel are driven by an enginerather than an electric motor.

In addition, it is preferable for at least part of the electric motor tobe disposed below the second power transmission member, the third powertransmission member or the differential mechanism, so that the secondpower transmission member, the third power transmission member or thedifferential mechanism overlaps in a vertical direction view. The spacebelow the second power transmission member, third power transmissionmember or differential mechanism is effectively used as the spacearranging the electric motor. In addition, the electric motor,differential mechanism, second power transmission member and third powertransmission member are arranged compactly in the vertical direction ofthe vehicle. For this reason, the electric motor is arranged at a lowposition in the vertical direction. It thereby becomes possible to makea lower center of gravity.

In addition, it is preferable for an end on an other side than the oneside in relation to the center in the front/rear direction of the leftwheel or the right wheel is located more to the other side than an endon an other side than the one side in relation to the center in thefront/rear direction of the electric motor. The electric motor isthereby arranged at the front. For this reason, it becomes possible toincrease the crash stroke during collision.

Effects of the Invention

According to the present invention, it is possible to provide a vehiclewhich is capable of achieving lowering of the center of gravity of avehicle having an electric motor, capable of ensuring large capacity atthe upper side of the front compartment, and capable of achieving anincrease in crash stroke and protection of the passenger space.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an outline plan view showing a vehicle 3 according to a firstembodiment of the present invention;

FIG. 2 is an outline side view showing the vehicle 3 according to thefirst embodiment of the present invention;

FIG. 3 is a skeleton expansion plan showing the vehicle 3 according tothe first embodiment of the present invention;

FIG. 4 is a collinear figure showing a relationship between a sun gear310, carrier 313 and ring gear 312 of a reduction mechanism 305 for anelectric motor 300 of the vehicle 3 according to the first embodiment ofthe present invention;

FIG. 5 is a skeleton expansion plan showing a vehicle 3A according to asecond embodiment of the present invention;

FIG. 6 is a collinear figure showing a relationship between a sun gear310, carrier 313 and ring gear 312 of a reduction mechanism 305A for anelectric motor 300 of the vehicle 3A according to the second embodimentof the present invention;

FIG. 7 is an outline side view showing a vehicle 3B according to a thirdembodiment of the present invention;

FIG. 8 is an outline side view showing a vehicle 3C according to afourth embodiment of the present invention;

FIG. 9 is an outline side view showing a vehicle 3D according to a fifthembodiment of the present invention;

FIG. 10 is a skeleton expansion plan showing a vehicle 3D according to afifth embodiment of the present invention;

FIG. 11 is an outline side view showing a vehicle 3E according to asixth embodiment of the present invention;

FIG. 12 is an outline side view showing a vehicle 3F according to aseventh embodiment of the present invention;

FIG. 13 is an outline plan view showing a reduction mechanism 305G foran electric motor 300G of a vehicle according to an eighth embodiment ofthe present invention;

FIG. 14 is a skeleton expansion plan showing a vehicle 3G according tothe eighth embodiment of the present invention; and

FIG. 15 is a collinear figure showing a relationship between a sun gear310G, ring gear 312G and carrier 313G for an electric motor 300G of thevehicle according to the eighth embodiment of the present invention.

PREFERRED MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the first embodiment of the present invention will beexplained in detail while referencing the drawings. It should be notedthat, in the explanations of the second and later embodiments, the samereference symbols will be attached for configurations, etc. shared withthe first embodiment, and explanations thereof will be omitted.

First Embodiment

FIG. 1 is an outline plan view showing a vehicle 3 according to thefirst embodiment of the present invention. FIG. 2 is an outline sideview showing the vehicle 3 according to the first embodiment of thepresent invention. FIG. 3 is a skeleton expansion plan showing thevehicle 3 according to the first embodiment of the present invention.FIG. 4 is a collinear figure showing a relationship between a sun gear310, carrier 313 and ring gear 312 of a reduction mechanism 305 of anelectric motor 300 of the vehicle 3 according to the first embodiment ofthe present invention. In FIGS. 1 and 2, the left side in the drawingsis the forward side of the vehicle 3, and the right side in the drawingsis the rear side of the vehicle 3.

As shown in FIG. 1, the vehicle 3 according to the present embodiment isan electric vehicle (electric automobile (EV)) which causes left/rightfront wheels LWf, RWf to drive with the electric motor 300 configured bya motor having a rotor 301 (refer to FIG. 3) and stator 302 as the powersource.

The vehicle 3 includes a drive device equipped with the electric motor300, an electronic control unit (hereinafter referred to as “ECU”) 6serving as a control unit which controls the electric motor 300, a PDU(power drive unit) 8, and a battery 9. The drive device includes theelectric motor 300 including an output shaft 303 and bevel gear 304; adifferential mechanism 400 including a differential ring 401; anintermediate shaft 321; a left-front drive shaft 501; and a right-frontdrive shaft 502. The electric motor 300 is provided at the front of thevehicle 3. The electric motor 300 drives the front wheels Wf (RWf, LWf)via the bevel gear 304, intermediate shaft 321, differential mechanism400, left-front drive shaft 501 and right-front drive shaft 502.

The electric motor 300, for example, is a three-phase AC motor of largerdiameter having a U-phase, V-phase and W-phase, and generates torque forrunning the vehicle 3, by way of electric power stored in the battery 9.The electric motor 300 is connected to the battery 9 via the PDU 8 whichincludes an inverter. By the driver depressing the accelerator pedal orbrake pedal, electric power supplied from the battery 9 to the electricmotor 300, and energy regeneration from the electric motor 300 to thebattery 9 are controlled by control signals from the ECU 6 beinginputted to the PDU 8.

In addition, to each of the front wheels Wf (RWf,

LWf) and rear wheels Wr (RWr, LWr), a friction brake (not illustrated)is provided. This friction brake, for example, is configured by ahydraulic disk brake. When the driver depresses the brake pedal, thedepression force is amplified and transmitted via hydraulic cylinders,etc. to the brake pads, and by the friction force generating between thebrake disk mounted to each drive wheel and the brake pad, braking ofeach drive wheel is performed.

Next, the configuration of each part of the drive device of the vehicle3 according to the present embodiment will be explained. As shown inFIGS. 2 and 3, in the electric motor 300, the rotation axis of the rotor301 and the output shaft 303 of the electric motor 300 arranged at aposition matching the rotation axis, are arranged so as to extend in thevertical direction of the vehicle 3. The rotor 301 of the electric motor300 is connected to the output shaft 303 of the electric motor 300 viathe reduction mechanism 305. The output shaft 303 of the electric motor300 is arranged more to the front side than the shaft center of thedifferential ring 401. More specifically, the reduction mechanism 305 isconfigured by a planetary gear mechanism having a sun gear 301,planetary pinion gear 311 (hereinafter referred to as planetary pinion),and ring gear 312, and the sun gear 310 is provided to the rotor 301 ofthe electric motor 300 to be integrally rotatable in a concentricpositional relationship with the rotor 301.

The sun gear 310 engages with the planetary pinion 311, and theplanetary pinion 311 engages with the ring gear 312. The ring gear 312is fixed to a case (not illustrated) which houses the rotor 301 andstator 302. The carrier 313 which rotatably and revolvably supports theplanetary pinion 311 is provided to be integrally rotatable with theoutput shaft 303 of the electric motor 300. The sun gear 310, carrier313 and ring gear 312 are configured so that the rotation speeds ofthese satisfy the collinear relationship aligning on a single line inthis aligning sequence on the velocity collinear chart (also referred ascollinear chart), as shown in FIG. 4. Herein, in the chart showing therelationship of revolution speed (rotation speed) between each rotatingelement of the planetary gear mechanism, the distance from thehorizontal line indicating value 0 until the white circle of thevertical axis in the collinear chart represents the revolution speed ofeach rotating element. In addition, in the alignment chart, the spacingof each rotating element on the horizontal axis represents therevolution speed ratio between each rotating element in the alignmentchart. At an end of the output shaft 303 of the electric motor 300, thebevel gear 304 has a coaxial positional relationship with the outputshaft 303 of the electric motor 300, and is provided to integrallyrotate with the output shaft 303 of the electric motor 300.

The intermediate shaft 321 is arranged so as to extend along theextending direction of the left-front drive shaft 501, and right-frontdrive shaft 502. In other words, the intermediate shaft 321 is arrangedin a positional relationship extending in the vehicle width direction ofthe vehicle 3 (left/right direction of vehicle 3; vertical direction inFIG. 1), and at both ends of the intermediate shaft 321, the bevel gear322 and the helical gear 323 are respectively provided to be integrallyrotatable with the intermediate shaft 321 coaxially. The bevel gear 322at one end of the intermediate shaft 321 engages with the bevel gear 304of the output shaft 303 of the electric motor 300. The differential ring401 has a ring gear configured by a helical gear provided to thedifferential case 403 of the differential mechanism 400. The front ofthe differential ring 401 engages with the rear of the helical gear 323of another end of the intermediate shaft 321. The differential ring 401is thereby mechanically coupled to the electric motor 300. Therefore,the bevel gear 304, intermediate shaft 321 and differential ring 401transfer the torque of the rotor 301 of the electric motor 300 to thedifferential mechanism 400. The rotor 301 of the electric motor 300 isarranged so as to be located lower than the bevel gear 304, intermediateshaft 321 and differential ring 401, in the up/down direction (verticaldirection), as shown in FIG. 2.

As shown in FIG. 3, the differential mechanism 400 has a left-side gear402, differential case 403, right-side gear 404 and differential pinion405, and is arranged on the power transmission path of the electricmotor 300, left-front wheel LWf and right-front wheel RWf.

The left-side gear 402 is mechanically connected to the left-front wheelLWf via the left-front drive shaft 501. The right-side gear 404 ismechanically connected to the right-front wheel RWf via the right-frontdrive shaft 502. The differential case 403 rotatably and revolvablysupports the differential pinion 405. The differential pinion 405engages with the left-side gear 402 and right-side gear 404,respectively. The differential mechanism 400 is configured so that thethree revolution speeds (rotating speed) of the left-side gear 402,differential case 403 and right-side gear 404 satisfy the collinearrelationship aligning on a single line, in a collinear chart (not shown)in this aligning sequence. It should be noted that FIG. 3 is a skeletonexpansion plan from a rear view of the vehicle 3, and differing fromFIGS. 1 and 2, FIG. 3 is drawn in a form depicting only the differentialmechanism 400. In other words, the bevel gear 304 and left-front driveshaft 501 and right-front drive shaft 402 are actually arranged atsubstantially the same height.

As shown in FIG. 1, the rear of the electric motor 300 overlaps with theleft-front drive shaft 501 and differential mechanism 400 in a verticaldirection view (plan view), and is arranged below the left-front driveshaft 501 and differential mechanism 400 as shown in FIG. 2. Then, asshown in FIG. 2, the electric motor 300 is arranged so that the upperend of the electric motor 300, i.e. upper end part of the output shaft303 of the electric motor 300, is located above the lower end of thedifferential ring 401 of the differential mechanism 400 in the vehiclewidth direction view (side view). Furthermore, in the vehicle widthdirection view, the shaft center of the differential ring 401 is abovethe upper end of the electric motor 300, and the electric motor isarranged so as to be located below the bevel gear 304, intermediateshaft 321 and the upper end of the differential ring 401. Furthermore,in the vehicle width direction view, the electric motor 300 is arrangedso that part of the rotor 301 of the electric motor 300 is located lowerthan part of the differential mechanism 400, and in more detail, thelower end of the differential ring 401 of the differential mechanism 400is located lower than the upper end of the rotor 301 (refer to FIG. 3).

In addition, as shown in FIGS. 1 and 2, the electric motor 300 isarranged so that the shaft center of the output shaft 303 of theelectric motor 300 matching the rotating shaft line of the rotor 301(refer to FIG. 3) of the electric motor is located on one side relativeto the center in the front/rear direction of the vehicle 3 (forward sidein present embodiment) than the left-front drive shaft 401, right-frontdrive shaft 502 (refer to FIG. 1) and differential mechanism 400. Then,in the front/rear direction of the vehicle 3, the ends of theleft/right-front wheels LWf, RWf (rear end of the left/right-frontwheels LWf, RWf in the present embodiment) near the center of thevehicle 3 are located closer to the center of the vehicle 3 (rearwardside in present embodiment) than the end of the electric motor near thecenter of the vehicle 3 (rear end of the electric motor 300 in presentembodiment). In addition, in the vehicle width direction view, the frontend of the differential mechanism 400 is located more to the rearwardside than the front end of the electric motor 300, and the rear end ofthe differential mechanism 400 is located more to the forward side thanthe rear end of the electric motor 300. In addition, the electric motor300 is arranged below the left-front drive shaft 501 in a vehicle widthdirection view. More specifically, the electric motor 300 is arranged sothat the rotor 301 is located more downward than the left-front driveshaft 501 and right-front drive shaft 502 in the vehicle width directionview.

According to the present embodiment, the following effects are exerted.In the present embodiment, the left-front wheel LWf and right-frontwheel RWf are arranged biased to the forward side as one side relativeto the center in the front/rear direction of the vehicle 3. The electricmotor 300 is arranged so that the rotation axis of the rotor 301 extendsin the vertical direction of the vehicle 3, and is arranged so that therotor 30 is located lower than the bevel gear 304, intermediate shaft321 and differential ring 401 arranged on the power transmission pathbetween the electric motor 300 and differential mechanism 400, andfurther, is arranged so that the rotation axis of the rotor 301 of theelectric motor 300 is located more to a forward side serving as one siderelative to the center in the front/rear direction of the vehicle 3,than the left-front drive shaft 501 arranged on the power transmissionpath between the left-side gear 402 and left-front wheel LWf, theright-front drive shaft 502 arranged on the power transmission pathbetween the right-side gear 404 and right-front wheel RWf, and thedifferential mechanism 400.

The crash stroke during collision of the front of the vehicle 3 therebyincreases. For this reason, it becomes possible to protect the passengerspace more. In addition, since the rotor 301 is arranged so as to belocated lower than the bevel gear 304, intermediate shaft 321 anddifferential ring 401, the electric motor 300 is arranged at a lowerposition in the vertical direction. For this reason, it becomes possibleto make the vehicle 3 lower center of gravity. In addition, it becomespossible to secure the volume (spatial capacity) on the upper side ofthe front compartment corresponding to the engine room of the vehicle inwhich the front wheels are driven by an engine rather than an electricmotor. In addition, since the rotation axis of the rotor 301 is arrangedso as to extend in the vertical direction of the vehicle 3, the electricmotor 300 becomes a configuration in which the radial direction of therotor 301 of the electric motor 300 matches the horizontal direction.For this reason, it becomes possible to use a larger diameter motor asthe electric motor 300. In addition, it is possible to secure thecapacity (spatial volume) of the front compartment without harming thedesign or drivability of the vehicle 3.

In addition, the left-front drive shaft 501 and right-front drive shaft502 are located more rearwards in the front/rear direction of thevehicle 3 than the rear end part of the electric motor 300. The electricmotor 300 is thereby arranged closer to the rear end of the vehicle 3.As a result thereof, it is possible to further increase the crash strokeduring collision of the front of the vehicle 3, and thus it becomespossible to further protect the passenger space.

In addition, the electric motor 300 is arranged so that the rotor 301 islocated lower than the left-front drive shaft 501, right-front driveshaft 502 and differential mechanism 400. For this reason, the electricmotor 300 is arranged at a lower position in the vertical direction. Forthis reason, it becomes possible to make the vehicle 3 lower center ofgravity. In addition, it is possible to secure capacity (spatial volume)on the upper side of the front compartment.

In addition, a part of the electric motor 300 is arranged downwards soas to overlap the left-front drive shaft 501 and differential mechanism400, in a vertical direction view. The space below the left-front driveshaft 501 and differential mechanism 400 is effectively used as thespace arranging the electric motor 300. In addition, the electric motor300, and the left-front drive shaft 501 and differential mechanism 400are arranged compactly in the vertical direction of the vehicle 3. Forthis reason, the electric motor 300 is arranged at a low position in thevertical direction. It thereby becomes possible to make a lower centerof gravity.

In addition, in the front/rear direction of the vehicle 3, the ends ofthe left-front wheel LWf and right-front wheel RWf (rear end ofleft-front wheel LWf and right-front wheel RWf) near the center of thevehicle 3 are located closer to the center of the vehicle 3 than the endof the electric motor 300 near the center of the vehicle 3 (rear end ofelectric motor 300). The electric motor 300 is thereby arranged asforward as possible. The crash stroke during collision of the front ofthe vehicle 3 thereby increases. As a result thereof, it becomespossible to protect the passenger space more.

In addition, the electric motor 300 is arranged so that the rotationalaxis of the rotor 301 extends in the vertical direction of the vehicle3; the rotor 301 is arranged so as to be located lower than the bevelgear 304 of the output shaft 303 of the electric motor 300, theintermediate shaft 321 and the differential ring 401 arranged on thepower transmission path between the electric motor 300 and differentialmechanism 400, and further, at least part of the electric motor 300 isarranged below the left-front drive shaft 501 and differential mechanism400 arranged on the power transmission path between the left-side gear402 and left-front wheel LWf in a vertical direction view.

The space below the left-front drive shaft 501 and differentialmechanism 400 is thereby effectively used as the space arranging theelectric motor 300. In addition, the electric motor 300, differentialmechanism 400 and left-front drive shaft 501 is arranged compactly inthe vertical direction of the vehicle 3.

For this reason, the electric motor 300 is arranged at a low position inthe vertical direction. It thereby becomes possible to make a lowercenter of gravity.

In addition, the intermediate shaft 321 is arranged so as to extendalong the extending direction of the left-front drive shaft 501 andright-front drive shaft 501. The electric motor 300 is arranged belowthe left-front drive shaft 501 in a vehicle width direction view.

It thereby becomes a positional relationship in which the electric motor300 is offset in the vehicle width direction relative to thedifferential mechanism 400 in a front view. For this reason, it becomespossible to effectively use the space at the front of the vehicle 3. Inaddition, in the front/rear view of the vehicle 3, it becomes possibleto compactly arrange the electric motor 300, differential mechanism 400,left-front drive shaft 501, and right-front drive shaft 502.

In addition, the upper end of the electric motor 300 is arranged so asto be located above the lower end of the differential mechanism 400 inthe vehicle width direction view. The electric motor 300, differentialmechanism 400, left-front drive shaft 501 and right-front drive shaft502 are thereby arranged more compactly in the vertical direction of thevehicle 3. For this reason, it is possible to secure volume (spatialcapacity) on the upper side of the front compartment. In addition, itbecomes possible to achieve lowering of the center of gravity of thevehicle 3 having a larger diameter electric motor 300.

In addition, in the vehicle width direction view, the shaft center ofthe differential ring 401 is arranged so as to be located above theupper end of the electric motor 300, and below the upper end of thebevel gear 304 of the output shaft 303 of the electric motor 300,intermediate shaft 321 and differential ring 401. In the verticaldirection of the vehicle 3, the electric motor 300, differentialmechanism 400, bevel gear 304, intermediate shaft 321 and differentialring 401 are thereby arranged more compactly. For this reason, it ispossible to secure volume (spatial capacity) on the upper side of thefront compartment. In addition, it becomes possible to achieve loweringof the center of gravity of the vehicle 3 having a larger diameterelectric motor 300.

In addition, in the vehicle width direction view, the electric motor 300is arranged so that the bevel gear 304, intermediate shaft 321 anddifferential ring 401 are located between the end of the electric motor300 on the forward side, which is one side relative to the center in thefront/rear direction of the vehicle 3, and the end of the electric motor300 on the rearward side, which is another side relative to the centerin the front/rear direction of the vehicle 3, in the front/reardirection of the vehicle 3. In the front/rear direction of the vehicle3, the electric motor 300, bevel gear 304, intermediate shaft 321,differential ring 401 and differential mechanism 400 are therebyarranged compactly. For this reason, it is possible to greatly protectthe passenger space without harming the design and drivability of thevehicle 3.

Second Embodiment

A vehicle 3A according to a second embodiment of the present inventiondiffers compared to the vehicle 3 according to the first embodiment onlyin the reduction mechanism 305A from the rotor 301 until output shaft303 of the electric motor 300. FIG. 5 is a skeleton expansion planshowing a vehicle 3A according to a second embodiment of the presentinvention. FIG. 6 is a collinear chart showing a relationship between asun gear 310, carrier 313 and ring gear 312 of a reduction mechanism305A for an electric motor 300 of the vehicle 3A according to the secondembodiment of the present invention. More specifically, the sun gear 310engages with the planetary pinion 311, and the planetary pinion 311engages with the ring gear 312A. The carrier 313A which rotatably andrevolvably supports the planetary pinion 311 is fixed to the case (notillustrated) housing the rotor 301 and stator 302. The output shaft 303of the electric motor 300 is provided to be integrally rotatable withthe ring gear 312A. The sun gear 310, carrier 313A and ring gear 312Aare configured so that the revolution speeds of these satisfy thecollinear relationship aligning on a single line in this aligningsequence on the velocity collinear chart (also referred as collinearchart), as shown in FIG. 4.

Third Embodiment

A vehicle 3B according to a third embodiment of the present inventiondiffers compared to the vehicle 3 according to the first embodiment, inthe position of the electric motor 300 relative to the left-front driveshaft 501 and right-front drive shaft 502. FIG. 7 is an outline sideview showing a vehicle 3B according to the third embodiment of thepresent invention.

More specifically, the electric motor 300 is arranged so that the shaftcenter of the output shaft 303 of the electric motor 300, which matchesthe rotation axis of the rotor 301 of the electric motor 300, is locatedmore to the other side (rearward side in present embodiment) relative tothe front/rear direction center of the vehicle 3, than the left-frontdrive shaft 501, right-front drive shaft 502 (refer to FIG. 1), anddifferential mechanism 400. The rear part of the differential ring 401engages with the front part of the helical gear 323 on the other end ofintermediate shaft 321. For this reason, the intermediate shaft 321 isarranged at the rearward side in the front/rear direction of the vehicle3B, relative to the left-front drive shaft 501 and right-front driveshaft 502. In addition, the output shaft 303 of the electric motor 300is arranged more to the rearward side than the shaft center of thedifferential ring 401.

Fourth Embodiment

A vehicle 3C according to a fourth embodiment of the present inventiondiffers compared to the vehicle 3 according to the first embodiment inthe point of not having the intermediate shaft 321. In addition, thedifferential ring 401C differs in the point of being configured by abevel gear. FIG. 8 is an outline side view showing a vehicle 3Caccording to the fourth embodiment of the present invention.

Since the vehicle 3C does not have the intermediate shaft 321, it has aconfiguration in which the rear part of the bevel gear 304 of the outputshaft 303 of the electric motor 300 and the front part of the ring gearof the differential ring 401C engage directly. For this reason, theportion on the left side of the rear part of the electric motor 300overlaps with the left-front drive shaft 501 in the vertical directionview (plan view), and is arranged below the left-front drive shaft 501.In addition, the portion on the right side at the rear part of theelectric motor 300 overlaps with the right-front drive shaft 502 in avertical direction view (plan view), and is arranged below theright-front drive shaft 502. In addition, the portion at the center ofthe rear part of the electric motor 300 overlaps with the differentialmechanism 400 in the vertical direction view (plan view), and isarranged below the differential mechanism 400. According to theabove-mentioned configuration, since the intermediate shaft 321 becomesunnecessary, the constituent elements for the transmission of motivepower from the electric motor 300 until the differential mechanism 400decrease, whereby it becomes possible to achieve size reduction, weightreduction and cost savings of the vehicle 3C. In addition, since thelocations at which gears engage decrease, it becomes possible to improvethe transmission efficiency of torque from the electric motor 300(decrease torque loss).

Fifth Embodiment

A vehicle 3D according to a fifth embodiment of the present invention,compared to the vehicle 3 according to the first embodiment, differs inthe extending direction of the intermediate shaft 321. In addition, adifferential ring 401D differs in the point of being configured by abevel gear, and the point of a bevel gear 323D which engages with thedifferential ring 401D being used in place of the helical gear 323. FIG.9 is an outline side view showing the vehicle 3D according to the fifthembodiment of the present invention. FIG. 10 is a skeleton expansionplan showing the vehicle 3D according to a fifth embodiment of thepresent invention.

It should be noted that, in FIG. 10, for convenience of explanation, thedifferential mechanism 400 is illustrated to be expanded so as to makethe left-front drive shaft 501 and right-front drive shaft 502 connectedby the differential mechanism 400 become a positional relationship inwhich the longitudinal direction of these points in the verticaldirection of FIG. 10. In practice, the left-front drive shaft 501 andright-front drive shaft 502 extend in a direction linking the nearbyside (surface side) and back side (reverse side) of the paper plane ofFIG. 10. It should be noted that FIG. 10 is a skeleton expansion planaccording the vehicle-width direction view of vehicle 3, but differsfrom FIGS. 1 and 2 so that the left-front drive shaft 501 andright-front drive shaft 502 appear in FIG. 10, and depicts in a formexpanding only the differential mechanism 400.

More specifically, the intermediate shaft 321 is arranged so as toextend along the front/rear direction of the vehicle 3D. For thisreason, the entirety of the electric motor 300 is arranged so as to belocated more to the front side, which is one side relative to the centerin the front/rear direction of the vehicle 3D, than the left-front driveshaft 501 and right-front drive shaft 502. In addition, the electricmotor 300 is arranged so that the left-front drive shaft 501 andright-front drive shaft 502 are located more to the rear side of thevehicle 3 than the end of the electric motor 300 at the rearward side ofthe vehicle 3.

According to the present embodiment, the following effects are exerted.In the present embodiment, the intermediate shaft 321 is arranged so asto extend along the front/rear direction of the vehicle 3D.

The intermediate shaft 321 is thereby arranged so as to extend in thefront/rear direction of the vehicle body. For this reason, it becomes apositional relationship in which the electric motor 300 is offsetrelative to the differential mechanism 400 in a side view. For thisreason, the electric motor 300 is arranged closer to the front end ofthe vehicle 3D. As a result thereof, it is possible to further increasethe crash stroke during collusion of the front part of the vehicle 3D,and thus becomes possible to further protect the passenger space.

In addition, the electric motor 300 is arranged so that the left-frontdrive shaft 501 and right-front drive shaft 502 are located more to therearward side of the vehicle 3 than the end of the electric motor 300 atthe rearward side of the vehicle 3. The electric vehicle 300 is therebyarranged closer to the front end of the vehicle 3D. As a result thereof,it is possible to further increase the crash stroke during collision ofthe front part of the vehicle 3D, and thus it becomes possible tofurther protect the passenger space.

Sixth Embodiment

A vehicle 3E according to a sixth embodiment of the present invention,compared to the vehicle 3 according to the first embodiment, differs inthe point of the electric motor 300 driving the rear wheels Wr (RWr,LWr), and the point of the one side relative to the center in thefront/rear direction of the vehicle 3E indicating the rearward side.FIG. 11 is an outline side view showing the vehicle 3E according to thesixth embodiment of the present invention.

More specifically, in the differential mechanism 400, the left-side gear402 (refer to FIG. 3, etc.) is mechanically connected to the left-rearwheel LWr via a left-rear drive shaft 503. The right-side gear 404(refer to FIG. 3, etc.) is mechanically connected to the right-rearwheel RWr (refer to FIG. 1, etc.) via a right-rear drive shaft (notillustrated). In addition, the rear part of the differential ring 401engages with the front part of the helical gear 323 on the other end ofthe intermediate shaft 321. For this reason, the intermediate shaft 321is arranged more to the forward side (center side) in the front/reardirection of the vehicle 3E than the left-rear drive shaft 503 andright-rear drive shaft (not illustrated).

The electric motor 300 is thereby arranged closer to the rear end of thevehicle 3E. For this reason, it is possible to further increase thecrash stroke during collision of the rear part of the vehicle 3E, andthus it becomes possible to further protect the passenger space.

Seventh Embodiment

A vehicle 3F according to a seventh embodiment of the present invention,compared to the vehicle 3E according to the sixth embodiment, differs inthe position of the left-rear drive shaft 503 and right-rear drive shaft(not illustrated) relative to the intermediate shaft 321. FIG. 12 is anoutline side view showing the vehicle 3F according to the seventhembodiment of the present invention.

More specifically, the front part of the differential ring 401 in thedifferential mechanism 400 engages with the rear part of the helicalgear 323 at the other end of the intermediate shaft 321. For thisreason, the intermediate shaft 321 is arranged more to the rearward sidein the front/rear direction of the vehicle 3F than the left-rear driveshaft 503 and the right-rear drive shaft (not illustrated).

Eighth Embodiment

A vehicle according to an eighth embodiment of the present invention,compared to the vehicle 3 according to the first embodiment, differs inthe configuration of the reduction mechanism 305G of an electric motor300G. FIG. 13 is an outline plan view showing the reduction mechanism305G of the electric motor 300G of the vehicle according to the eighthembodiment of the present invention. FIG. 14 is a skeleton expansionplan showing a vehicle 3G according to the eighth embodiment of thepresent invention. FIG. 15 is a collinear chart showing a relationshipbetween a sun gear 310G, ring gear 312G and carrier 313G of the electricmotor 300G of the vehicle according to the eighth embodiment of thepresent invention.

More specifically, the reduction mechanism 305G of the electric motor300G may be configured by planetary gears of double pinion form, asshown in FIGS. 13 and 14. The ring gear 312G corresponding to the ringgear 312 of the first embodiment thereby is located in the center in thecollinear chart as shown in FIG. 15, and the revolution speed ratio isequally divided. In other words, the sun gear 310, carrier 313, and ringgear 312 of the first embodiment correspond to the sun gear 310G, ringgear 312G and carrier 313G of the present embodiment, respectively. Thesun gear 310G engages with the one pinion of the planetary pinion(double pinion) 311G, and the other pinion of the planetary pinion 311Gengages with the one pinion and the ring gear 312G. The ring gear 312Gis fixed to a case (not illustrated) housing the rotor 301 and stator302. The output shaft 303 of the electric motor 300 is provided to beintegrally rotatable with the carrier 313G supporting the planetarypinion 311G to be rotatable and revolvable. The sun gear 310G, ring gear312G and carrier 313G are configured so that the revolution speeds ofthese satisfy the collinear chart aligning on a single line in thisaligning order, in the velocity collinear chart (also referred ascollinear chart).

In this way, the reduction mechanism 305G of the electric motor 300G isconfigured by planetary gears of double pinion form; therefore, itbecomes possible to raise the degrees of freedom in design such as thesetting of revolution speed ratio.

It should be noted that the present invention is not limited to theabove-mentioned embodiments, and that modifications, improvements, etc.in a scope that can achieve the objects of the present invention areencompassed by the present invention.

For example, the left wheel and right wheel driven by the electric motorare not limited to either the left-front wheel and right-front wheel, orleft-rear wheel and right-rear wheel driven in the above-mentionedrespective embodiments. More specifically, the present embodimentsshowed the sixth embodiment illustrated in FIG. 11 in which the electricmotor 300 drives the left-rear wheel LWr and right-rear wheel RWr,relative to the first embodiment illustrated in FIG. 2, in which theelectric motor 300 drives the left-front wheel LWf and right-front wheelRWf; and showed the seventh embodiment illustrated in FIG. 12 in whichthe electric motor 300 drives the left-rear wheel LWr and right-rearwheel RWr, relative to the third embodiment illustrated in FIG. 7 inwhich the electric motor 300 drives the left-front wheel LWf andright-front wheel RWf. In contrast, the fourth embodiment shown in FIG.8 and the fifth embodiment shown in FIG. 9 describe only configurationsin which the electric motor 300 drives the left-front wheel LWf andright-front wheel RWf; however, in this way, it may be configured sothat the electric motor 300 drives the left-rear wheel LWr andright-rear wheel RWr instead of a configuration in which the electricmotor 300 drives the left-front wheel LWf and right-front wheel RWf. Inaddition, it may be configured so as to combine the configuration shownin FIG. 2 and the configuration shown in FIG. 11 to drive the fourwheels of the left/right-front wheels and the left/right-rear wheels.

In addition, the positional relationship in the front/rear direction ofthe vehicle 3 between the rotation axis of the rotor 301 of the electricmotor 300 and the left-front drive shaft 501, right-front drive shaft502 or differential mechanism 400 is not limited to the positionalrelationship of the above-mentioned embodiment. For example, whereas thefirst embodiment illustrated in FIG. 2 in which the rotational axis ofthe rotor 301 of the electric motor 300 is located more to one siderelative to the front/rear direction center of the vehicle 3 (forwardside, which is a side distanced from the front/rear direction center ofthe vehicle 3), than the left-front drive shaft 501, right-front driveshaft 502 and differential mechanism 400, the third embodimentillustrated in FIG. 7 showed that the rotational axis of the rotor 301of the electric motor 3 is located more to the other side (rearward sidein present embodiment) relative to the front/rear direction center ofthe vehicle 3 than the left-front drive shaft 501, right-front driveshaft 502 and differential mechanism 400. Similarly, in the fourthembodiment shown in FIG. 8, the electric motor 300 may be arranged sothat the rotation axis of the rotor 301 of the electric motor 300 islocated on the other side to the center of the front/rear direction ofthe vehicle 3 (rear side which is side close to the front/rear directioncenter of the vehicle 3), relative to the left-front drive shaft 501,right-front drive shaft 502 and differential mechanism 400. In addition,at least part of the electric motor 300 may be arranged so as to belocated on one side of the front/rear direction center of the vehicle 3,relative to the left-front drive shaft 501, right-front drive shaft 502and differential mechanism 400.

In addition, at least part of the electric motor 300 may be arrangedbelow the left-front drive shaft 501, right-front drive shaft 502 ordifferential mechanism 400, so as to overlap the left-front drive shaft501, right-front drive shaft 502 or differential mechanism 400 in avertical direction view. In addition, at least part of the electricmotor 300 may be arranged below the left-front drive shaft 501 orright-front drive shaft 502 in a vehicle-width direction view.

In addition, the reduction mechanism reducing the speed and transferringthe rotation of the rotor 301 to the output shaft 303 in the electricmotor 300 is not limited to the reduction mechanisms 305, 305A and 305Gin the present embodiment.

In addition, the configurations of each part of the vehicle are notlimited to the configurations of each part of the vehicle 3 according tothe present embodiment. For example, the differential mechanism 400 hasthe left-side gear 402, differential case 403, right-side gear 404, anddifferential pinion 405; however, it is not limited to thisconfiguration. For example, the differential mechanism may be configuredby a planetary gear of double pinion type. A ring gear corresponding tothe differential case 403 of the first embodiment is located at thecenter in the collinear figure, and the sun gear or carriercorresponding to the left-side gear 402 or right-side gear 404 ismechanically connected to the left/right front wheels.

In addition, in the first embodiment shown in FIG. 2, although theelectric motor 300 is arranged so that the rotation axis of the rotor301 extends up/down in a substantially vertical direction, the electricmotor 300 may be arranged so that the rotation axis extends obliquelyup/down so as to intersect the vertical direction.

In addition, the vehicle 3 of the above-mentioned embodiment is anelectric vehicle (electric automobile (EV)) which drives the left/rightfront wheels LWf, RWf or left/right rear wheels LWr, RWr with a motorserving as the electric motor 300 as the source of power; however, it isnot limited thereto. For example, the vehicle may be a hybrid vehicle(HEV) having an internal combustion engine such as an engine and anelectric motor, in which the electric motor drives the wheels(left/right front wheels, left/right rear wheels); a plug-in hybrid(PHEV) having an internal combustion engine such as an engine and anelectric motor, in which the electric motor drives the wheels(left/right front wheels, left/right rear wheels), and is capable ofcharging a battery via an attachment plug from a power source outsidethe vehicle; a fuel cell vehicle (FCV) which drives an electric motorusing electricity generated by a fuel cell, in which an electric motordrives the wheels (left/right front wheels, left/right rear wheels); ora plug-in fuel cell vehicle (PFCV) which drives an electric motor usingelectricity generated by a fuel cell and electricity charged to thebattery via an attachment plug from a power source outside the vehicle,in which the electric motor drives the wheels (left/right front wheels,left/right rear wheels).

EXPLANATION OF REFERENCE NUMERALS

3, 3A, 3B, 3C, 3D, 3E, 3F vehicle

300, 300G electric motor

301 rotor

302 stator

304 bevel gear

321 intermediate shaft

400 differential mechanism

401 differential ring

402 left-side gear

403 differential case

404 right-side gear

501 left-front drive shaft

502 right-front drive shaft

504 left-rear drive shaft

LWf, Rwf left/right front wheels (left wheel, right wheel, one wheel,other wheel)

1. A vehicle comprising: an electric motor which drives a left wheel anda right wheel of the vehicle, and has a rotor and a stator; and adifferential mechanism which has three rotating elements, and configuredso that rotation speeds of the three rotating elements satisfy acollinear relationship on a single line in a collinear figure, whereinthe differential mechanism is disposed on a power transmission pathbetween the electric motor to which a propeller shaft is not provided,and the left wheel and the right wheel, and torque is transmitted froman upper end of an output shaft of the electric motor to thedifferential mechanism, wherein, when defining the three rotatingelements as a first rotating element, a second rotating element and athird rotating element in arrangement order of the collinear figure, thefirst rotating element is mechanically connected to one wheel, which iseither one among the left wheel and the right wheel, wherein the secondrotating element is mechanically connected to the electric motor,wherein the third rotating element is mechanically connected to theother wheel which is the other one among the left wheel and the rightwheel, wherein the left wheel and the right wheel are disposed biasingto one side relative to a center in a front/rear direction of thevehicle, wherein the electric motor is disposed so that the rotationaxis of the rotor extends along a vertical direction of the vehicle, andis disposed so that the rotor is located lower than a first powertransmission member disposed on a power transmission path between theelectric motor and the differential mechanism, and further is arrangedso that the rotation axis of the rotor of the electric motor is disposedso as to be located more to the one side relative to the front/reardirection center in relation to: a second power transmission memberdisposed on the power transmission path between the first rotatingelement and the one wheel, a third power transmission member disposed onthe power transmission path between the third rotating element and theother wheel, or the differential mechanism.
 2. The vehicle according toclaim 1, wherein the first power transmission member includes: a firstrotating body disposed on a side of the electric motor on the powertransmission path; a second rotating body disposed on a side of thedifferential mechanism on the power transmission path; and a thirdrotating body interposed between the first rotating body and the secondrotating body, wherein the third rotating body is disposed so as toextend in the front/rear direction of the vehicle, and wherein at leastpart of the electric motor is disposed so as to be located to the oneside relative to the center in the front/rear direction, in relation tothe second power transmission member, the third power transmissionmember or the differential mechanism.
 3. The vehicle according to claim2, wherein the second power transmission member or the third powertransmission member is located more to the other side relative to thecenter in the front/rear direction than an end on another side than theone side in relation to the center of the front/rear direction of theelectric motor.
 4. The vehicle according to claim 1, wherein theelectric motor is disposed so that the rotor is located more downwardsthan the second power transmission member, the third power transmissionmember or the differential mechanism.
 5. The vehicle according to claim4, wherein at least part of the electric motor is disposed below thesecond power transmission member, the third power transmission member orthe differential mechanism, so that the second power transmissionmember, the third power transmission member or the differentialmechanism overlaps in a vertical direction view.
 6. The vehicleaccording to claim 1, wherein an end on an other side than the one sidein relation to the center in the front/rear direction of the left wheelor the right wheel is located more to the other side than an end on another side than the one side in relation to the center in the front/reardirection of the electric motor.